1. Field
The present disclosure relates generally to manufacturing and, in particular, to a method and apparatus for processing workpieces. Still more particularly, the present disclosure relates to a method and apparatus for controlling the properties of metal workpieces.
2. Background
Metal parts may be heated to high temperatures to achieve desired material properties. It may be desirable to quickly reduce the temperature of the metal to obtain certain material properties. The metal parts may then be quenched to rapidly cool the metal and lock in the material properties. Quenching may include subjecting the hot parts to a liquid or gas. For example, dropping the hot parts into a container of liquid may be a form of quenching. Placing the hot parts in the path of a moving gas, such as an airstream, may also be a form of quenching.
Differences in part geometry may cause uneven cooling rates during quenching. Uneven cooling rates may result in at least one of warpage or residual stresses. The warpage or residual stresses may result in unacceptable geometric variations. Further, uneven cooling rates may result in a difference in mechanical properties between different areas of the part.
When warpage occurs, the part being formed may need to be reworked and/or scrapped. Further, parts with undesirable amounts of stresses may need to be scrapped. These situations may increase the time and/or cost needed to manufacture parts. As a result, assembly and manufacturing of products may need more time and may incur more costs than desired.
It would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above, as well as other possible issues. For example, it may be desirable to have a method and apparatus to reduce residual stresses in quenched metal workpieces. Further, it may be desirable to have a method and apparatus to obtain substantially consistent material properties throughout a quenched metal workpiece.